Internalization of Nanoparticles in the Middle Ear Epithelium in Response to an External Magnetic Field: Generating a Force

In this study we report the first generation of force by long-term intracellular magnetic nanoparticles (MNP) using a guinea pig middle ear model. Synthesis of magnetite nanoparticles was done using a modified precipitation technique. We used different methods to characterize MNP. The mechanism for internalizing 16 ± 2.3 nm diameter, silica coated, superparamagnetic, MNP was likely magnetically enhanced endocytosis. During the surgery a rare earth, permanent magnet (0.35 Tesla) placed under the animal was used to pull the MNP into the tissue. After 8 days, following euthanasia, tissues were harvested and confocal scanning laser interferometry used to verify intracellular MNP. Displacements of the osscicular chain in response to an external sinusoidal electromagnetic field were measured. Laser Doppler interferometry, measured, for the first time, a normal biomechanical function enabled by intracellular MNP.